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Re: [libvirt] PATCH: 15/25: Prohibit non-threadsafe POSIX apis



There are a huge list of functions in POSIX which are not
safe to use from multiple threads currently. I generated
the list by looking at all libc symbol exports for variants
which have a parallel _r symbol.

   nm -D --defined-only /lib/libc.so.6  \
      | grep '_r$' \
      | awk '{print $3}' \
      | grep -v __ \
      | grep -v qsort \
      | grep -v readdir \
      | sort \
      | uniq \
      | sed -e 's/_r//'

The qsort one is a red herring, since you only need qsort_r if
you need to pass a extra 'void * opaque' data blob to your sort
function - we don't, so don't need qsort_r.

The readdir one is also unneccessary, since reading from a single
DIR* is safe from a single thread. readdir_r is also horrific

http://womble.decadentplace.org.uk/readdir_r-advisory.html


This patch adds a 'make sc_prohibit_nonrentrant' rule to the
'syntax-check' for these forbidden functions.

 .x-sc_prohibit_nonreentrant |    8 ++++
 Makefile.am                 |    2 +
 Makefile.maint              |   11 +++++
 Makefile.nonreentrant       |   85 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 106 insertions(+)

Daniel

diff --git a/.x-sc_prohibit_nonreentrant b/.x-sc_prohibit_nonreentrant
new file mode 100644
--- /dev/null
+++ b/.x-sc_prohibit_nonreentrant
@@ -0,0 +1,8 @@
+^gnulib/
+^po/
+ChangeLog
+^Makefile*
+^docs/
+^tests/
+^src/virsh.c
+^build-aux/
diff --git a/Makefile.am b/Makefile.am
--- a/Makefile.am
+++ b/Makefile.am
@@ -17,6 +17,8 @@ EXTRA_DIST = \
   .x-sc_require_config_h_first \
   .x-sc_prohibit_strcmp \
   .x-sc_require_config_h \
+  .x-sc_prohibit_nonreentrant \
+  Makefile.nonreentrant \
   autogen.sh
 
 man_MANS = virsh.1
diff --git a/Makefile.maint b/Makefile.maint
--- a/Makefile.maint
+++ b/Makefile.maint
@@ -12,6 +12,8 @@ VC_LIST = $(srcdir)/build-aux/vc-list-fi
 
 VC_LIST_EXCEPT = \
   $(VC_LIST) | if test -f .x-$@; then grep -vEf .x-$@; else grep -v ChangeLog; fi
+
+include Makefile.nonreentrant
 
 # Prevent programs like 'sort' from considering distinct strings to be equal.
 # Doing it here saves us from having to set LC_ALL elsewhere in this file.
@@ -110,6 +112,15 @@ sc_prohibit_asprintf:
 sc_prohibit_asprintf:
 	@grep -nE '\<[a]sprintf\>' $$($(VC_LIST_EXCEPT)) && \
 	  { echo '$(ME): use virAsprintf, not a'sprintf 1>&2; exit 1; } || :
+
+sc_prohibit_nonreentrant:
+	@fail=0 ; \
+	for i in $(NON_REENTRANT) ; \
+	do \
+	   grep -nE "\<$$i\>[:space:]*\(" $$($(VC_LIST_EXCEPT)) && \
+	     fail=1 && echo "$(ME): use $${i}_r, not $${i}" || : ; \
+	done ; \
+	exit $$fail
 
 # Using EXIT_SUCCESS as the first argument to error is misleading,
 # since when that parameter is 0, error does not exit.  Use `0' instead.
diff --git a/Makefile.nonreentrant b/Makefile.nonreentrant
new file mode 100644
--- /dev/null
+++ b/Makefile.nonreentrant
@@ -0,0 +1,85 @@
+
+#
+# Generated by running the following on Fedora 9:
+#
+#  nm -D --defined-only /lib/libc.so.6  \
+#      | grep '_r$' \
+#      | awk '{print $3}' \
+#      | grep -v __ \
+#      | grep -v qsort \ # Red herring since we don't need to pass extra args to qsort comparator
+#      | grep -v readdir \ # This is safe as long as each DIR * instance is only used by one thread
+#      | sort \
+#      | uniq \
+#      | sed -e 's/_r//'
+#
+
+NON_REENTRANT =
+NON_REENTRANT += asctime
+NON_REENTRANT += ctime
+NON_REENTRANT += drand48
+NON_REENTRANT += ecvt
+NON_REENTRANT += erand48
+NON_REENTRANT += ether_aton
+NON_REENTRANT += ether_ntoa
+NON_REENTRANT += fcvt
+NON_REENTRANT += fgetgrent
+NON_REENTRANT += fgetpwent
+NON_REENTRANT += fgetspent
+NON_REENTRANT += getaliasbyname
+NON_REENTRANT += getaliasent
+NON_REENTRANT += getdate
+NON_REENTRANT += getgrent
+NON_REENTRANT += getgrgid
+NON_REENTRANT += getgrnam
+NON_REENTRANT += gethostbyaddr
+NON_REENTRANT += gethostbyname2
+NON_REENTRANT += gethostbyname
+NON_REENTRANT += gethostent
+NON_REENTRANT += getlogin
+NON_REENTRANT += getmntent
+NON_REENTRANT += getnetbyaddr
+NON_REENTRANT += getnetbyname
+NON_REENTRANT += getnetent
+NON_REENTRANT += getnetgrent
+NON_REENTRANT += getprotobyname
+NON_REENTRANT += getprotobynumber
+NON_REENTRANT += getprotoent
+NON_REENTRANT += getpwent
+NON_REENTRANT += getpwnam
+NON_REENTRANT += getpwuid
+NON_REENTRANT += getrpcbyname
+NON_REENTRANT += getrpcbynumber
+NON_REENTRANT += getrpcent
+NON_REENTRANT += getservbyname
+NON_REENTRANT += getservbyport
+NON_REENTRANT += getservent
+NON_REENTRANT += getspent
+NON_REENTRANT += getspnam
+NON_REENTRANT += getutent
+NON_REENTRANT += getutid
+NON_REENTRANT += getutline
+NON_REENTRANT += gmtime
+NON_REENTRANT += hcreate
+NON_REENTRANT += hdestroy
+NON_REENTRANT += hsearch
+NON_REENTRANT += initstate
+NON_REENTRANT += jrand48
+NON_REENTRANT += lcong48
+NON_REENTRANT += localtime
+NON_REENTRANT += lrand48
+NON_REENTRANT += mrand48
+NON_REENTRANT += nrand48
+NON_REENTRANT += ptsname
+NON_REENTRANT += qecvt
+NON_REENTRANT += qfcvt
+NON_REENTRANT += random
+NON_REENTRANT += rand
+NON_REENTRANT += seed48
+NON_REENTRANT += setstate
+NON_REENTRANT += sgetspent
+NON_REENTRANT += srand48
+NON_REENTRANT += srandom
+NON_REENTRANT += strerror
+NON_REENTRANT += strtok
+NON_REENTRANT += tmpnam
+NON_REENTRANT += ttyname

-- 
|: Red Hat, Engineering, London   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-  F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|


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